# Ceramic Hang Assembly Manual

## Scope

This manual covers the first ceramic handpan-inspired tonal vessel prototypes. It assumes the instrument is slip-cast from upper and lower shell molds and validated as a research build before decorative finishing.

## Tools And Setup

- CAD model for upper shell, lower shell, tone-field islands, gu, rim, and mold split.
- Large-format 3D printer or outsourced print service.
- Plaster mold-making setup: cottle boards, scale, bucket, plaster, mold release, clamps.
- Cone 6 casting slip and known firing schedule.
- Drying cradle and firing support ring.
- Calipers, scale, tuner, microphone, recording app, and spreadsheet/validation log.
- Diamond files/burrs for minimal cleanup.
- Kiln access.

## Process

1. **Make shrinkage bars**
   - Cast or form test bars from the actual clay body.
   - Fire through the intended bisque and glaze schedule.
   - Replace the assumed 12 percent shrinkage with measured data before final master printing.

2. **Build tone coupons**
   - Make small raised/thinned field coupons before a full shell.
   - Vary thickness, field diameter, relief depth, and clay body.
   - Record pitch, decay, cracking, and perceived strike feel.

3. **Model the first shell**
   - Model the fired target geometry first.
   - Apply `master_scale_factor = 1/(1 - shrinkage)`.
   - Keep the first upper shell conservative: fewer undercuts, larger radii, and enough wall thickness to survive handling.

4. **Print and seal masters**
   - Print upper and lower shell masters or segments.
   - Fill segment seams, sand, and seal.
   - Mark centerline, tone-field index, rim datum, and gu center.

5. **Make plaster molds**
   - Build cottle boxes with enough plaster thickness for a large dome.
   - Include registration and mold handling features.
   - Dry molds fully before slip casting.

6. **Slip cast shells**
   - Cast upper and lower shells separately.
   - Record slip batch, pour time, drain time, demold time, room condition, and measured wall thickness.
   - Support shells in a cradle as they stiffen.

7. **Join and refine**
   - Join upper/lower shells at leather-hard stage.
   - Smooth seam and rim.
   - Keep post-join tone-field carving minimal and documented.

8. **Dry slowly**
   - Dry under plastic with frequent inspection.
   - Watch tone-field edges, gu, rim seam, and support contact points.

9. **Bisque fire and measure**
   - Fire to the clay body's recommended bisque schedule.
   - Measure every tone field and the gu/body resonance before glazing.
   - Decide whether to continue, revise the mold, or return to coupons.

10. **Finish test**
    - Test glaze or oxide on coupons before the full body.
    - If glazing the full shell, leave tone-field strike zones and acoustic edges as controlled test variables.

11. **Final validation**
    - Record pitch, cents error, decay time, body mode, gu response, crack status, and playability.
    - Feed results back into the next design table revision.

## Shop Notes

- Do not chase final tuning on the first shell. The first shell is a measurement object.
- Never grind aggressively on fired tone fields.
- Add a protective rim strategy early; ceramic rims are vulnerable.
- Treat transport as a design requirement, not an afterthought.